The California Quarries Corporation began mining pumice here in 1927. Pumice is a type of lightweight, volcanic stone used as an abrasive, among other things. In 1947 a 70-ton mill was built. I'm not sure if these ruins are from the 1947 facility or an earlier mill. The mill ruins are on private property so I was unable to get any closeup photos of the equipment.

I visited this site in June 2024.